Estimation of blood glucose by O-Toluidine Method

 O-Toluidine Method (a method of blood glucose Estimation)

This O-Toluidine Method  makes use of the principle that glucose reacts specifically with o-toluidine, an aromatic amine, in glacial acetic acid at 100°C to produce a blue-green color. 

• This color can be measured colorimetrically. The method has the additional advantage that it can be performed directly on serum, plasma, cerebrospinal fluid or urine without deproteinization. 

• The O-toluidine method is no longer widely used today because O-toluidine is believed to be a carcinogen.

Reference Range of Normal Values

• Fasting blood glucose level: For adults-3.3-5.6 mmol/L or 60-100 mg/di
• For children----2.5-5.0 mmol/L or 45-90 mg/dl
• Post-prandial blood glucose: up to 6.9 mmol/L or up to 125 mg/dl.
• Random blood glucose: 3.3-7.4 mmol/L or 60 - 132 mg/dl.

Note

• Reference range of blood sugar level is about 20 mg/dl or 1.1 mmol/L more than the true glucose level.

Interpretation of Test Results

• A raised blood glucose level is called hyperglycaemia, where as a low glucose level is known as hypoglycaemia. 

• Mild or transient hyperglycaemia may also occur following injury and diseases of certain glands such as pituitary, adrenal and thyroid.  

Transient hypoglycaemia

1. Acute alcohol ingestion

2. Drugs such as salicylates, anti-tuberculosis agents

3. Severe liver diseases

4. Glycogen storage disorder

5. Hereditary fructose intolerance

6. Kwashiorkor (malnutrition)

7. Addison's disease

8. Neonatal hypoglycaemia

 

Causes of Abnormal Glucose Levels
Severe hyperglycaemia	Mild/transient hyperglycaemia	Severe hypoglycaemia
1. Diabetes mellitus	1. Severe liver disease	1. Insulinoma
2. Adrenal cortical hyperactivity (Cushing's syndrome)	2. Pancreas disorder	2. Hypopituitarism
3. Acromegaly	3. Pituitary disorder	3. Ectopic insulin production from tumours
4. Obesity	4. Steroid therapy	4. Adrenal cortical insufficiency
	5. Shock 6. Convulsions
	7. Acute stress reaction (Physical or emotional)